Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already state this is a non-readOnly, non-destructive, closed-world tool, and the description adds useful behavior beyond that: it creates a pending audio item filled with MP3 on an SFX track and costs credits. It does not explain async status checking or what happens if the SFX track is missing, but the added cost and placement details are valuable.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short sentences, front-loaded with the core action and followed by the practical placement rule and cost note. Every sentence earns its place with no wasted text.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the full schema and annotations, the description covers the essential behavior: generation, MP3 fill, SFX track placement, start timing, and credit cost. It could be stronger by naming search_sfx as the alternative for pre-existing effects or by pointing to generation_status/job_status for completion, but it is largely complete for invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the schema already documents all six parameters, including defaults and constraints. The description reinforces `start` as the timeline second for the effect and mentions the default SFX track, but does not add meaning beyond the schema for the other parameters.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource (generate a sound effect) and adds placement behavior (on an SFX track, filling a pending audio item with MP3). It does not explicitly distinguish itself from siblings like search_sfx or generate_music, but the action is clear enough without opening the schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives clear usage context: place one per moment, set `start` to the timeline second it belongs to, and note that it costs credits. It does not mention when to prefer search_sfx for existing effects or when not to generate, so it lacks explicit alternatives or exclusions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.